Re: [PATCH v8 0/5] vfio-pci support pasid attach/detach

[Alex Williamson <alex.williamson@redhat.com>]

On Thu, 13 Mar 2025 05:47:48 -0700
Yi Liu <yi.l.liu@intel.com> wrote:

> This series introduces the PASID attach/detach user APIs (uAPIs) that
> allow userspace to attach or detach a device's PASID to or from a specified
> IOAS/hwpt. Currently, only the vfio-pci driver is enabled in this series.
> 
> Following this update, PASID-capable devices bound to vfio-pci can report
> PASID capabilities to userspace and virtual machines (VMs), facilitating
> PASID use cases such as Shared Virtual Addressing (SVA). In discussions
> about reporting the virtual PASID (vPASID) to VMs [1], it was agreed that
> the userspace virtual machine monitor (VMM) will synthesize the vPASID
> capability. The VMM must identify a suitable location to insert the vPASID
> capability, including handling hidden bits for certain devices. However,
> this responsibility lies with userspace and is not the focus of this series.
> 
> This series begins by adding helpers for PASID attachment in the vfio core,
> then extends the device character device (cdev) attach/detach ioctls to
> support PASID attach/detach operations. At the conclusion of this series,
> the IOMMU_GET_HW_INFO ioctl is extended to report PCI PASID capabilities
> to userspace. Userspace should verify this capability before utilizing any
> PASID-related uAPIs provided by VFIO, as agreed in [2]. This series depends
> on the iommufd PASID attach/detach series [3].
> 
> The complete code is available at [4] and has been tested with a modified
> QEMU branch [5].

What's missing for this to go in and which tree will take it?  At a
glance it seems like 4/ needs a PCI sign-off and 5/ needs an IOMMUFD
sign-off.  Thanks,

Alex